There are known various types of loading apparatus for loading and unloading of cargo in an aircraft. Known loading apparatus has commonly included a structural base or frame which is supported with respect to the aircraft cargo door by either the ground, the aircraft itself or by both. A cargo platform or cargo container carrier typically is provided and an elevation means is associated with the structural base and the cargo platform to move the cargo platform between the ground and an elevated position adjacent the aircraft cargo hold floor.
The various known loading apparatus often are of specialized design and application owing to the wide variety of existing aircraft designs. For example, some aircraft are loaded and unloaded through a nose door whereas others are provided with side cargo doors. Each of these and other cargo loading arrangements may require specialized loading apparatus.
Often prior aircraft loaders have been intended to be carried by the aircraft and deployed therefrom for loading and unloading of cargo. This has been desirable as a given aircraft often may be receiving or discharging cargo at a location where no suitable loading and unloading equipment is available. This may be particularly true in the operations of military aircraft, for example.
The prior art is replete with examples of known aircraft loaders, of which the following are exemplary. U.S. Pat. Nos. 3,885,685 and 3,972,427 disclose front-end or nose loading apparatus which are at least partially supported in the operative position by the ground. U.S. Pat. Nos. 2,701,068, 3,478,904, 3,776,492, 3,861,542 and 3,944,087 disclose various loading apparatus in which a cargo platform, typically a cantilevered platform, rides between ground level and the aircraft cargo floor on rails which are deployed from the aircraft to an operative position. U.S. Pat. Nos. 2,950,073, 3,463,334, 3,552,587 and 3,952,974 all disclose loaders which are carried by an aircraft and which include a containerized cargo carrier or a cargo platform suspended from a support frame that is in turn supported by the aircraft adjacent the cargo door. Of these patents, U.S. Pat. Nos. 3,463,334 and 3,552,587, disclose suspension frames which are deployed from the aircraft adjacent the uppermost extent of the cargo door by being rolled laterally outward of the cargo door on tracks from a stowed position within the aircraft. U.S. Pat. No. 2,950,073 discloses a frame including a pair of cantilevered arms which are located to extend laterally outward from the threshold of the aircraft cargo door. U.S. Pat. No. 3,952,974 discloses a cargo platform which is suspended by chains from a cargo door of an aircraft, the chains being passed over drive sprockets which are connected to a sprocket drive system for lifting the platform along vertical tracks which are deployed from the aircraft. U.S. Pat. No. 3,661,415 discloses a cable winching system for hoisting a cargo platform or container with respect to an overhead support of indeterminate structure.
The prior art of aircraft loading apparatus as typified by the above has been subject to certain shortcomings. For example, in those prior loaders incorporating a cargo platform suspended by plural cables from a suspension frame, each cable may be passed about a series of guide pulleys and reeved on the drum of a powered hoist. The guide pulleys, and in some cases the hoist, typically are supported in part by the overhead suspension frame from which the cargo platform is suspended. The suspension frame therefore must be of sufficient strength to support the large tension loads in each run of cable passing between each pair of adjacent guide pulleys. As a result, prior suspension frames have often been of significantly greater weight and design complexity than would otherwise be required merely to support the hanging weight of the cargo platform and its cargo. Related shortcomings have included adverse impact on operational simplicity, reliability, and structural economy. In the case of onboard loaders, aircraft payload has also been adversely affected to the extent that the loader weight or space requirements are not minimized. Other shortcomings of prior loaders include unduly complex mechanical arrangements for storage thereof in and deployment from the aircraft.
Another shortcoming of prior loaders concerns the structural configuration of the suspension frames utilized in suspension type on-board loaders. Many such prior loaders have included a suspension frame located adjacent the top of the aircraft cargo hold door, that is, spaced upwardly form the cargo hold floor, because in the process of lifting the platform and the cargo carried thereby the suspension frame structure was apt to interfere with the cargo. Thus, the suspension frame was spaced upwardly from the elevation of the cargo hold floor in order to ensure that a loaded cargo platform could be lifted up to the cargo hold floor without interference with the suspension frame. The run of suspension cable between the frame and the platform thus is considerably longer than desirable and as a result the suspended platform may be less stabile than desired. Auxiliary structural elements may be required in such systems to stabilize the cargo platform, but this sort of expedient represents a distinct departure from integrated system design practice and results in undesirable additional weight and consequent aircraft payload penalty.